United States Department of Agriculture

Animal and Plant Health Inspection Service

Plant Protection and Quarantine

Survey Protocol for Interstate Movement of Citrus 

Nursery Stock from Areas Quarantined for Citrus 

Canker, Citrus Greening, and/or Asian Citrus Psyllid

2019

In support of the APHIS Citrus Nursery Stock Final Rule (Docket# APHIS-2010-0048), this 

survey protocol is for citrus nursery stock (CNS) intended for interstate movement from APHISapproved exclusionary facilities in areas quarantined for citrus greening (CG), Asian citrus 

psyllid (ACP), and/or citrus canker (CC). Inspection, sampling, and testing requirements for 

allowing interstate movement of CNS are described (USDA, 2008 and 2019). 

Detection Survey for CC: An inspector must visually inspect plants for disease symptoms at an 

interval not to exceed 30 calendar days. Leaves from plants showing symptoms of CC must be 

tested using Work Instructions approved by APHIS.

Detection Survey for ACP: An inspector must visually inspect new flush growth of CNS for 

ACP at an interval not to exceed 30 calendar days. Any suspect specimens should be submitted 

to an APHIS approved identifier. Visual inspection can be augmented by using yellow sticky 

cards (1 card per 1000 ft2), vacuum suction sampling, tap sampling, or other methods approved 

by APHIS.

Detection Survey for CG: An inspector must visually inspect plants for disease symptoms at an 

interval not to exceed 30 calendar days. Leaves from plants showing symptoms of CG must be 

tested by a diagnostician certified by APHIS at a laboratory accredited by APHIS using the 

APHIS Work Instruction. CG plant tissue sampling and testing must be conducted according to 

the schedule in Table 1.

Table 1. Testing intervals for different citrus nursery stock tree types.

Tree Type Testing Interval

Mother/scion ALL mother/scion plants must be tested once per 

calendar year at an interval not less than 11 months

and not more than 12 months

Increase A sample of increase trees must be tested every 6 

months – see Table 2 for rate of sampling

Production trees: sold prior to 12 months of age Testing is not required

Production trees: held for 12 months or longer Trees must be tested at 12 months and every 6 months 

thereafter – see Table 2 for rate of sampling

Tissue samples must be collected from plants randomly selected from the lot. Tissue samples 

must be tested by a diagnostician certified by APHIS at a laboratory accredited by APHIS using 
the APHIS Work Instruction. Table 2 provides required sample sizes for testing of citrus nursery 

stock for interstate movement. 

Table 2. Sampling size required for citrus nursery stock lots eligible for interstate movement.

Plants per Lot1 Number of Plants to Sample2 Number of Laboratory Tests 

Required3

1 to 100 All plants 1 to 25

101 to 200 160 40

201 to 300 195 49

301 to 400 220 55

401 to 500 230 58

501 to 1,000 265 67

1,001 to 1,500 275 69

1,501 to 2,000 280 70

2,001 to 2,500 285 72

2,501 to 3,000 290 73

3,001 to 3,500 295 74

> 3,500 300 75

1

A lot is defined as the population of plants to be tested (i.e. mother plants, increase trees, etc.). 2

Each plant sample consists of 8 leaves. 3

Laboratory tests may be run on a composite sample taken from one to four citrus plants (8-32 leaves).

Supporting Documents:

USDA. 2008. New Pest Response Guidelines Citrus Greening Disease. United States 

Department of Agriculture. 

USDA. 2019. Interstate Movement of Citrus Nursery Stock from Areas Quarantined for Citrus 

Canker, Citrus Greening, and/or Asian Citrus Psyllid – November 25, 2019. United 

States Department of Agriculture.